EIGRP Route Not in Topology Table or Routing Table
Presenting Symptom
A route that should be learned via EIGRP is not present in the topology table or the routing table.
Network Context
This issue occurs in a small branch office with two Cisco routers (R1 and R2) running IOS 15.x. R1 is connected to the WAN and should learn a route to a remote subnet (192.168.10.0/24) via EIGRP from R2. The EIGRP neighbor adjacency is established, but the route is missing from R1's topology and routing tables.
Diagnostic Steps
Check EIGRP neighbors
show ip eigrp neighborsH Address Interface Hold Uptime SRTT RTO Q Seq 0 10.1.1.2 Gi0/0 13 00:15:30 12 200 0 45
If the neighbor is listed, the adjacency is up. If not, check Layer 1/2 connectivity and EIGRP configuration. If neighbor is present, proceed to next step.
Verify EIGRP topology table
show ip eigrp topology all-linksP 192.168.10.0/24, 1 successors, FD is 28160
via 10.1.1.2 (28160/28160), GigabitEthernet0/0If the route appears in the topology table, it is learned but may not be installed in the routing table due to administrative distance or metric issues. If missing, the route is not being advertised or received.
Check EIGRP routes in routing table
show ip route eigrpD 192.168.10.0/24 [90/28160] via 10.1.1.2, 00:15:30, GigabitEthernet0/0
If the route is present, the problem is resolved. If not, the route is not being installed. Check for route filtering or administrative distance issues.
Verify EIGRP route advertisement
show ip eigrp topology 192.168.10.0/24P 192.168.10.0/24, 1 successors, FD is 28160
via 10.1.1.2 (28160/28160), GigabitEthernet0/0
via 10.1.1.3 (28416/28160), GigabitEthernet0/1If the route is in the topology table, it is being advertised. If not, check the advertising router's EIGRP configuration and network statements.
Check for distribute-lists or route filtering
show running-config | include distribute-listdistribute-list 10 in GigabitEthernet0/0
If a distribute-list is present, it may be filtering the route. Check the access-list to see if the route is permitted.
Root Cause
The route is missing because an inbound distribute-list on R1's GigabitEthernet0/0 interface is filtering the route. The access-list referenced by the distribute-list denies the subnet 192.168.10.0/24.
Resolution
Verification
Run 'show ip route eigrp' on R1. Expected output: D 192.168.10.0/24 [90/28160] via 10.1.1.2, 00:00:05, GigabitEthernet0/0
Prevention
1. Use route maps instead of distribute-lists for more granular control. 2. Always verify route filtering after applying distribute-lists. 3. Document all route filters and review during network changes.
CCNA Exam Relevance
On the CCNA 200-301 exam, this scenario tests troubleshooting of EIGRP route installation. Expect multiple-choice questions where you must identify why a route is missing, or drag-and-drop steps to resolve. Key fact: EIGRP routes must be in the topology table before being installed in the routing table; filtering can prevent this.
Exam Tips
Remember that 'show ip eigrp topology' shows all learned routes; if missing, the issue is with advertisement or filtering.
Distribute-lists can filter inbound or outbound; check both directions.
The 'show ip route' command shows only the best route; use 'show ip eigrp topology all-links' to see all potential routes.
Commands Used in This Scenario
show ip eigrp neighbors
Displays the neighbor table for EIGRP, showing all directly connected EIGRP routers and their status, used to verify EIGRP adjacencies and troubleshoot neighbor relationships.
show ip eigrp topology
Displays the EIGRP topology table, showing all learned routes and their feasible successors, used to verify EIGRP convergence and path selection.
show ip route
Displays the current IP routing table on a Cisco router, used to verify routes, check next-hop addresses, and troubleshoot connectivity issues.
Test Your CCNA Knowledge
Practice with scenario-based questions to prepare for the CCNA 200-301 exam.
Practice CCNA Questions